Proj 1: The discovery of reprogramming somatic cells to induced pluripotent stem cells has opened new dimensions for the study and treatment of human diseases. Since the first description of reprogramming mouse IPS cells by introducing 4 transcription factor genes with retroviral vectors, mouse and human cells of many cell types have been successfully reprogrammed. Although retroviral vectors are still the most proficient vehicles for reprogramming, their property of random integration may cause damage by disrupting vital host gene functions. Many other vehicles for introducing transcription factors have been reported, including plasmids, EB based plasmid vectors, adenoviral vectors, transposons, lentiviral vectors and proteins. Some of these methods are inefficient for reprogramming human somatic cells. Lentiviral vectors also integrate randomly into the genome although they could be removed with cre-lox. The aim of this project is to investigate novel IPS techniques that can be applied in the future to the treatment of sickle cell disease and B-thalassemia, the 2 most common genetic diseases. We will use 2 strategies. The first is to introduce the 4 transcription factor genes 0CT4, S0X2, FLT4 and cMYC linked by 2A peptides using PhiC31 integrase fpr site-specific integration. The second strategy, directed by the co-investigator Long-Cheng Li, will use his innovation of short activator double stranded RNA to stimulate the expression ofthe endogenous transcription factor genes. He has shown that these saRNAs can stimulate expression of endogenous genes of various kinds. The strategies we propose have the advantage of not disturbing the functions of the host genes. Our project is directed to eventual application to sickle cell disease and thalassemia. We will reprogram skin biopsy cells from patents as well as amniotic fluid and CVS cells which will be useful for early cell therapy after prenatal diagnosis.